Boiler



Sept. 4, 1928. n

T. E. MURRAY BOILER Filed July 1, 1925 351310 wma EMM@ Patented Sept. 4, 1928.

UNITED STATES PATENT OFFICE..

THOMAS E. MURRAY, OF BROOKLYN, NEW YORK.

Bomen.,

Application filed J'nly 1, 1925. Serial No. 40.746.

The present invention is Vdirected to boil.

ers operating on a similar princi-ple. The accompanying drawings illustrate an ems bodiment of t-he invention.

F ig. 1 is a horizontal section of the combustion chamber; r Fig. 2 is an enlarged detail thereof.

The combustion chamber is surrounded by i a metal wall 1 and referably a second wall 2 spaced outside of the rst so as to leave an air space for insulation and, if desired, for preheating the air for combustion. Within the main wallsthere is an inner wall s of tubular members spaced apart and presenting to the radiant heat of the burning fuel an area greater than that of the outer or main wall, these tubes carrying water and being connected to the main circulating sysi tem of the boiler (or to a separate circulatin system in some cases).

7arious arrangements of the tubing may be provided. In the case illustrated, I provide an outermost row of tubes 3, an intermediate row of tubes 4 and' an innermost row of tubes 5. The outer tubes 3 may be provided with flanges 6 on their rear faces overlappin so as to shield the main wall 1 and to catc all the heat rays projected from the burning fuel in the center constituting t-he combustion chamber. The other tubes may also be provided with flanges, but preferably they are plain so that there shall be no interferences with the passage of the heat rays between them. The tubes ofthe outer row and those of j the middle row are separated from each other by substantially the same spacing, those of one row being staggered with rela'- tion to those of the other. The tubes of the innermost row are doubleLspaced and rections of the heat rays. The entire chamber being filled with the flaming fuel, the tubes 5 are exposed to direct radiant heat overabout inches in a 12 inch circumference as indicated by the line 7 for the tubes 4 there is an exposure of about 9 inches in 12 as indicated by the line 8. For the tubes 3, as indicated by the line 9, there is an exposure of about 7 inches. The exposure of the fins as indicated by the lines 10 and 11 is about 30% of the total area. The total surface exposure is obviously much greater than the area of the outer wall l. The figures-given are approximate, and various other arrangements in principle and location, and also in size of the tubes may be designed so as to secure approximately the same results;

The furnace is arranged with nozzle burn A- ers 12 for projecting powdered, liquid or gaseous fuel. This may be in volume sufficiently to till the chamber to substantially the heightl of the tubes with incandescent gases so as to get the maximum radiant effect.

.The iinvention is particularly designed for hugh pressure stationary boilers, though it is applicable to various types of boiler. The same principle may be employed with less than four Water walls, one or more of the walls being of usual design and construction and protected in known ways. In that case the area of the tubular members exposed to the radiant heat should be greater than the projected area of the outer walls against which they lie and may indeed be greater than the total area of all the outer" walls. The outer Walls maybe provided, ,in addition to the arrangement shown, with ordinary insulating material on their outer faces. For greater efficiency it will generally be desirable to surmount the arrangement shown by the ordinary tubing to utilize the heat umts in the gases passing out of the combustion chamber. Such tubing above the chamber may bearranged in successive lines staggered as explained in connection with the drawing to secure a large exposure to the direct radiant heat.

The boiler of this invention can be designed to run at an extremely high rating. A boiler is run at 100% ratin according to modern standards when eac uare foot of surface evaporates 3.45 oun sof water from and at 212 degrees This is an average figure for the entire heating surface.4 However some parts of the surface, those farthest from the furnace in the line of draft of the gases, are very ineflicient and may not evaporate even one pound of water er uare foot. On the other hand, the surace irectly exposed to the radiant heat of the furnace is very efficient and may evaporate more than sixty pounds of water per square foot.

According to this invention the boiler is so constructed and arranged `that the proportion or percentage of the heating surface which is directly exposed to the radiant heat of the burning fuel may be considerably inf creased as compared with boilers hertofore built. The vlimitation of present boilers with ordinary refractory 'walls is in the inability of the walls to withstand the eXtreme heat liberated from the fuel if it is attem ted to run the boiler at a rating considerab y increased beyond its normal capacity according to ordinary standards. It 1s impossible to operate boilers of the common type at more than two or three times their normal capacity without deterioration of the Walls. When operating at such high ratings efficiency is sacrificed, as the proportions of the surface remote from the furnace are not efficient. The boiler of the` present invention has ,the maximum amount of surface exposed to the direct radiant heat of the furnace and, therefore, in the most efficient location. With this design the only limitation of the capacity is the ability to supply sufficient water through the tubes to protect the metal thereof, and this may be .accomplished by the use of suitable circulating systems such as I have ydescribed in other pending applications and by the use of larger water and steam pipes than usual.

With the ordinary industrial boiler it is dangerous to run beyond about of its rating because of the liability of the furnace wall to fail at the higher temperatures required.Y Boilers of the present design can be run at a much higher rating, well above 200% of the standard, and this without injury to the walls.

' The different lines of tubes illustrated may be all used for generating steam and may be in one or in several different circulatin systems. Or they may be used for di erent purposes such as steam generating, water heating, steam superheating and the like; that is, some of them for generating fresh steam, some for superheating and others for heating feed water.

Though I have described with great particularity of detail certain embodiments of my invention, yet it is not to be understood therefrom that the invention is restricted to particular embodiments disclosed. Various -modifications thereof may be made by those skilled in the art without departing from the invention as defined in the following claim.

What I claim is:

A boiler adapted to generate steam a high pressure having an outer wall and having an inner wall comprising a multiplicity' of tubular members of substantially the same diameter in rows at different distances from the outer wall, with the members of the innermost row spaced farther apart than those of the next row so as to permit greater surface exposure of the latter to the radiant heat of the burning fuel.

In witness whereof, I have hereunto signed my name.

THOMAS' E. MURRAY. 

